The present invention relates generally to fuel tanks for vehicles and, more particularly, to a fuel permeation resistant fuel tank for a vehicle.
It is known to provide a fuel tank such as a plastic fuel tank in a vehicle to hold fuel to be used by an engine of the vehicle. In some vehicles, the plastic fuel tank has a fuel permeation barrier made of an ethylene vinyl alcohol copolymer (EVOH). While EVOH is effective against permeation of pure hydrocarbon fuels, it has a high permeability when used with alcohol containing fuels.
One commercial approach to resolve this concern regarding permeation is to thicken the walls of the fuel tank, which increases the weight, cost and reduces fuel capacity of the fuel tank. Therefore, it is desirable to provide a fuel tank for a vehicle that has a more effective fuel permeation barrier to prevent evaporative emission. It is also desirable to provide a fuel permeation resistant fuel tank for a vehicle that significantly reduces evaporative emissions.
It is, therefore, one object of the present invention to provide a new fuel permeation resistant fuel tank for a vehicle.
It is another object of the present invention to provide a fuel tank that significantly reduces evaporative emissions in comparison to EVOH plastic tanks.
To achieve the foregoing objects, the present invention is a fuel permeation resistant fuel tank for a vehicle including a tank shell having a wall formed from a plurality of layers. The layers include at least an inner layer, an outer layer and a fuel permeation barrier layer between the inner layer and the outer layer and being made of a liquid crystalline polymer (LCP) material.
One advantage of the present invention is that a fuel permeation resistant fuel tank is provided for a vehicle that has a more effective fuel permeation barrier leading to less evaporative emissions. Another advantage of the present invention is that the fuel permeation resistant fuel tank uses liquid crystalline polymer (LCP) as the material for the barrier layer. Yet another advantage of the present invention is that the LCP adds high strength and stiffness to the fuel tank and is a good candidate for high pressure fuel vessels as compared to EVOH. Still another advantage of the present invention is that the fuel permeation resistant fuel tank uses LCP as the barrier layer, which has low permeation to fuels and very high modulus and strength. A further advantage of the present invention is that the use of these materials in a plastic fuel tank leads to a lighter tank.